Sponsored Content
Top Forums UNIX for Beginners Questions & Answers Usage of sed, position of apostrophe Post 303022811 by Aia on Friday 7th of September 2018 01:16:17 PM
Old 09-07-2018
Quote:
Originally Posted by baris35
Hello,
I have never ever seen below notation for string substitution.

Code:
sed -i -e 's/tttt/pppp'/g /var/bin/czech.sh;

The strange thing for me is the position of the apostrophe. Should it be before the / or after the g?
If I had been writing that command line, I would have chosen below way:
Code:
sed -i -s 's/tttt/pppp/g' /var/bin/czech.sh

Could you please explain what it differs...
Is that about the operating system?

Many thanks
Boris
Regular expressions uses meta-characters. These are characters that have special meaning beyond the representation of the character. The shell has also meta-characters. Therefore in order to protect the meaning of these characters it must be quoted so it gets passed to sed as the regular expression intended.
In this case the quoting could be avoided all together sed s/tttt/pppp/g /var/bin/czech.sh since there are no meta-characters.
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

translate text (1 position) with sed

Hello, I'm trying to translate a fixed length (the first 6 positions) that begins with a 0 to overwrite the field with an *. Any suggestion? File 1 ------- 013344 01:20 222343 19:30 233333 20:30 File 2 (result) ----------------- ****** 01:20 222343 19:30 233333 20:30 (5 Replies)
Discussion started by: peterk
5 Replies

2. HP-UX

how can I find cpu usage memory usage swap usage and logical volume usage

how can I find cpu usage memory usage swap usage and I want to know CPU usage above X% and contiue Y times and memory usage above X % and contiue Y times my final destination is monitor process logical volume usage above X % and number of Logical voluage above can I not to... (3 Replies)
Discussion started by: alert0919
3 Replies

3. Shell Programming and Scripting

How to replace symbols by position using SED

Hi all, I need your help. For example I have string in file.txt: -x -a /tmp/dbarchive_NSS_20081204 -f 900 -l 1 2008/12/04 2008/12/04 So, I need to replace symbols from (for e.g.) position 26 till 33 with symbols which I have in file replace.txt And I have no idea how to do it. If... (1 Reply)
Discussion started by: nypreH
1 Replies

4. Shell Programming and Scripting

Remove text from n position to n position sed/awk

I want to remove text from nth position to nth position couple of times in same line my line is "hello is there anyone can help me with this question" I need like this ello is there anyone can help me with question 'h' is removed and 'this' removed from the line. I want to do this... (5 Replies)
Discussion started by: elamurugu
5 Replies

5. Shell Programming and Scripting

Sed position specific replace

I'm drawing a blank on how to use sed to replace selectively based on position in the string (vs nth occurence): hello.|there.|how.|are.|you.| I want the period removed in the 3rd item (as defined by the pipe delimiter) if a period is present. So the result in this case would be: ... (2 Replies)
Discussion started by: tiggyboo
2 Replies

6. Shell Programming and Scripting

Replace apostrophe with backslash apostrophe

I'm coding using BASH and have a requirement to replace apostrophes with backslash apostrophes. For example below: I am here 'in my room' ok Would be changed to: I am here /'in my room/' ok The original text is coming from a field in a MySql database and is being used by another process that... (5 Replies)
Discussion started by: dbjock
5 Replies

7. Programming

How to change only one occurance of apostrophe with sed

Hi, I have a document with usual English text and some of the words have apostrophes (e.g. don't, can't, etc.) I would like all these apostrophes to be doubled (e.g. don''t, can''t, etc.), but the problem is, that some of such words have double apostrophe and by using sed -i "s/'/''/g"... (2 Replies)
Discussion started by: neptun79
2 Replies

8. Shell Programming and Scripting

Trying to move a column into another position within a sed script

Currently the table looks like this student-id,last,first,hwk1,hwk2,hwk3,exam1,hwk4,hwk5,exam2 pts-avail,,,100,150,100,200,100,150,300 991-78-7872,Thompson,Ken,95,143,79,185,95,135,259 123-45-6789,Richie,Dennis,99,123,89,189,97,139,279 234-56-7891,Aho,Al,78,146,75,176,88,128,285... (3 Replies)
Discussion started by: ertang
3 Replies

9. Shell Programming and Scripting

awk usage for position matching

i have a requirement like this if the line contains from position 294 to 299 is equal to "prabhu" ,then print entire line . i want to use awk awk '{if(substr(294-299) == 'prabhu') print "line" }' filename (1 Reply)
Discussion started by: ptappeta
1 Replies

10. UNIX for Dummies Questions & Answers

Using sed to insert at position x and then every interval y for each line

Thanks to help from Don Cragun in post 302924174, I'm off and getting into trouble on my own (finally) with sed. Here is my goal - insert \\r\n at the 60th character on each line and then every 76th character thereafter: Input:... (3 Replies)
Discussion started by: gusbrown
3 Replies
egrep(1)							   User Commands							  egrep(1)

NAME
egrep - search a file for a pattern using full regular expressions SYNOPSIS
/usr/bin/egrep [-bchilnsv] -e pattern_list [file...] /usr/bin/egrep [-bchilnsv] -f file [file...] /usr/bin/egrep [-bchilnsv] pattern [file...] /usr/xpg4/bin/egrep [-bchilnqsvx] -e pattern_list [-f file] [file...] /usr/xpg4/bin/egrep [-bchilnqsvx] [-e pattern_list] -f file [file...] /usr/xpg4/bin/egrep [-bchilnqsvx] pattern [file...] DESCRIPTION
The egrep (expression grep) utility searches files for a pattern of characters and prints all lines that contain that pattern. egrep uses full regular expressions (expressions that have string values that use the full set of alphanumeric and special characters) to match the patterns. It uses a fast deterministic algorithm that sometimes needs exponential space. If no files are specified, egrep assumes standard input. Normally, each line found is copied to the standard output. The file name is printed before each line found if there is more than one input file. /usr/bin/egrep The /usr/bin/egrep utility accepts full regular expressions as described on the regexp(5) manual page, except for ( and ), ( and ), { and }, < and >, and , and with the addition of: 1. A full regular expression followed by + that matches one or more occurrences of the full regular expression. 2. A full regular expression followed by ? that matches 0 or 1 occurrences of the full regular expression. 3. Full regular expressions separated by | or by a NEWLINE that match strings that are matched by any of the expressions. 4. A full regular expression that can be enclosed in parentheses ()for grouping. Be careful using the characters $, *, [, ^, |, (, ), and in full regular expression, because they are also meaningful to the shell. It is safest to enclose the entire full regular expression in single quotes (a'a'). The order of precedence of operators is [], then *?+, then concatenation, then | and NEWLINE. /usr/xpg4/bin/egrep The /usr/xpg4/bin/egrep utility uses the regular expressions described in the EXTENDED REGULAR EXPRESSIONS section of the regex(5) manual page. OPTIONS
The following options are supported for both /usr/bin/egrep and /usr/xpg4/bin/egrep: -b Precede each line by the block number on which it was found. This can be useful in locating block numbers by context (first block is 0). -c Print only a count of the lines that contain the pattern. -e pattern_list Search for a pattern_list (full regular expression that begins with a -). -f file Take the list of full regular expressions from file. -h Suppress printing of filenames when searching multiple files. -i Ignore upper/lower case distinction during comparisons. -l Print the names of files with matching lines once, separated by NEWLINEs. Does not repeat the names of files when the pattern is found more than once. -n Precede each line by its line number in the file (first line is 1). -s Work silently, that is, display nothing except error messages. This is useful for checking the error status. -v Print all lines except those that contain the pattern. /usr/xpg4/bin/egrep The following options are supported for /usr/xpg4/bin/egrep only: -q Quiet. Does not write anything to the standard output, regardless of matching lines. Exits with zero status if an input line is selected. -x Consider only input lines that use all characters in the line to match an entire fixed string or regular expression to be matching lines. OPERANDS
The following operands are supported: file A path name of a file to be searched for the patterns. If no file operands are specified, the standard input is used. /usr/bin/egrep pattern Specify a pattern to be used during the search for input. /usr/xpg4/bin/egrep pattern Specify one or more patterns to be used during the search for input. This operand is treated as if it were specified as -epat- tern_list.. USAGE
See largefile(5) for the description of the behavior of egrep when encountering files greater than or equal to 2 Gbyte ( 2^31 bytes). ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of egrep: LC_COLLATE, LC_CTYPE, LC_MES- SAGES, and NLSPATH. EXIT STATUS
The following exit values are returned: 0 If any matches are found. 1 If no matches are found. 2 For syntax errors or inaccessible files (even if matches were found). ATTRIBUTES
See attributes(5) for descriptions of the following attributes: /usr/bin/egrep +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ |CSI |Not Enabled | +-----------------------------+-----------------------------+ /usr/xpg4/bin/egrep +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWxcu4 | +-----------------------------+-----------------------------+ |CSI |Enabled | +-----------------------------+-----------------------------+ SEE ALSO
fgrep(1), grep(1), sed(1), sh(1), attributes(5), environ(5), largefile(5), regex(5), regexp(5), XPG4(5) NOTES
Ideally there should be only one grep command, but there is not a single algorithm that spans a wide enough range of space-time trade-offs. Lines are limited only by the size of the available virtual memory. /usr/xpg4/bin/egrep The /usr/xpg4/bin/egrep utility is identical to /usr/xpg4/bin/grep -E. See grep(1). Portable applications should use /usr/xpg4/bin/grep -E. SunOS 5.11 24 Mar 2006 egrep(1)
All times are GMT -4. The time now is 11:11 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy